Her mission was to disrupt enemy communications from Mulegé's garrison to other communities and fortifications. According to reports, the Mexican population of coastal towns grew terrified of the repeated appearances of Libertad in the waters off their settlements. No engagements occurred until October 31, when Tunis Craven spotted a Mexican merchant schooner, in the anchorage of Mulege at 10:00 pm.

Unknown to Craven at the time, the Mexican schooner was protected by an artillery battery of considerable strength at the mouth of the anchorage on Punta Sombrero, with several riflemen to guard the battery.

The American Lieutenant advanced his ship, but the Mexican batteries witnessed the attack and opened fire. Craven later reported the initiation of the action:

"I heard no sound ashore, but the passing of the sentry's call, till about half-past ten o'clock, when bang! bang! bang! they commenced from every direction. I jumped out of my bed, seized my gun and fired at the group nearest me, which I could only discern by the flashes of their guns".

The Libertad, well armed and prepared for action, immediately abandoned the attempt to capture a prize ship. Instead she opened fire on the Mexican batteries with her guns, one of which was a pivot gun which was set up in haste just after hostilities commenced. The Mexicans found themselves in a good defensive position that night.

The moon was rising behind the American vessel leaving her silhouetted against the horizon. This made the United States ship easier to see despite having to engage in an artillery duel at night. Craven ordered his men to fire on what appeared to be the largest concentrations of Mexican forces.

Craven reported that the Mexicans kept up a steady stream of cannonballs on their target, most of them however flew over the ship or passed just across Libertad '​s bow. The fighting lasted about two hours, slowly the batteries reduced their rate of fire before being mostly silenced at about 11:00 pm and by 12:00 midnight, all was quiet again.

No Americans were wounded that night. Libertad received slight damage to her sails and rigging but was otherwise unharmed. Mexican casualties are unknown as it was too dark to ascertain casualties from the American perspective. Lieutenant Craven decided not to send a land party ashore that night, so instead he proceeded to meet USS Dale off Guaymas but was too late to participate in the Bombardment of Guaymas.

Brooks, Nathan Covington (1849). A Complete History of the Mexican War: Its Causes, Conduct and Consequences: Comprising an Account of the Various Military and Naval Operations from Its Commencement to the Treaty of Peace. Philadelphia: Grigg, Elliot & Co.

The USS Libertad, tender ship of the USS Dale under command of Lieutenant T. A. M. Craven, USN, bombarding Punta Sombrero in the operation against the communications of Mexican troops at Muleje. 31 October 1847. From the collection of Franklin Delano Roosevelt.